Incontinence is a condition characterized by involuntary loss of urine, beyond the individual's control, that results in the loss or diminution of the ability to maintain the urethral sphincter closed as the bladder fills with urine. Male or female stress urinary incontinence (SUI) occurs when the patient is physically or emotionally stressed.
One cause for this condition is damage to the urethral sphincter or loss of support of the urethral sphincter, such as can occur in males after prostatectomy or following radiation treatment, or that can occur due to pelvic accidents and aging related deterioration of muscle and connective tissue supporting the urethra. Other causes of male incontinence include bladder instability, over-flowing incontinence and fistulas.
The female's natural support system for the urethra is a hammock-like supportive layer composed of endopelvic fascia, the anterior vaginal wall, and the arcus tendineus (a distal attachment to the pubic bone). Weakening and elongation of the pubourethral ligaments and the arcus tendineus fascia pelvis, weakening of the endopelvic fascia and pubourethral prolapse of the anterior vaginal wall, and their complex interaction with intraabdominal forces are all suspected to play a role in the loss of pelvic support for the urethra and subsequent hypermobility to an unnaturally low non-anatomic position, leading to urinary incontinence.
Females can also exhibit cystocele, a condition due to laxity of the pelvic floor wherein the bladder extrudes out and downwards causing SUI. The severity of this bladder collapse is rated between Grades one through four. In Grade four cystocele, the bladder extrudes out of the vaginal opening. The treatment of choice for this condition includes the reduction or closing of the pelvic floor opening from which the bladder descends using sutures. As noted below, other procedures involving implantation of a urethral sling are also gaining acceptance.
In general, continence is considered to be a function of urethral support and coaptation. For coaptation to successfully prevent or cure incontinence, the urethra must be supported and stabilized in its normal anatomic position.
The present application is directed to the treatment of SUI and chronic urinary incontinence due to inability of the urethral sphincter to close or remain closed as bladder fluid pressure builds. Currently, incontinence treatments of choice involve implantation of a Kaufman Prosthesis, an artificial sphincter (such as the AMS-800 Urinary Control System available from American Medical Systems, Inc.), or a urethral sling procedure in which a urethral sling is inserted beneath the urethra and advanced in the retro pubic space. Peripheral portions of the elongated urethral sling are affixed to bone or body tissue, and a central portion of the elongated urethral sling extends under the urethral or bladder neck to provide a platform that compresses the urethral sphincter, limits urethral distention, and pelvic drop, and thereby improves coaptation.
Male and female urethral sling procedures are disclosed in commonly assigned U.S. Pat. Nos. 6,652,450 and 6,382,214, for example, and further female urethral sling procedures are described in commonly assigned U.S. Pat. No. 6,641,524, for example, and publications and patents cited therein. The implantation of certain urethral slings involves the use of delivery systems configured for and techniques that involve transvaginal, transobturator, suprapubic and pre-pubic exposures or pathways.
The above-referenced '214 patent describes apparatus and methods for treatment of male incontinence and female cystocele repair in which a urethral sling material is positioned between the descending pubic rami of the pubic bone. In such an operation a “hammock-like” urethral sling material is sutured below the urethra in males, or below the posterior bladder wall in the case of cystocele in females. The urethral sling material may comprise synthetic material or cadaveric or autologous fascia and may or may not be absorbable over time.
In the male case, the urethral sling applies passive compression against the bulbar urethra. The compression, either by itself or in conjunction with urethral mobility, prevents urine leak during strain. If additional passive pressure is required on the urethra after surgery is completed, collagen or other bulky material can be injected with a tiny needle through the perineum, causing more pressure created by the bulky material on one side (the lower or caudal side) by the urethral sling, and on the other (the upper or superior) side compressing the urethra. An example of a urethral sling sutured to and extending between four bone screws fixed to the descending pubic rami is depicted in FIG. 12 of the above-referenced '214 patent.
One minimally invasive surgical procedure that incorporates the teachings of the above-referenced '214 patent to alleviate mild to moderate male SUI is performed employing the InVance™ Male Urethral Sling System for implanting the InteMesh™ Synthetic Surgical Mesh (both available from American Medical Systems, Inc.) in a manner generally described in the above-referenced '214 patent and depicted in FIGS. 1-3. The InteMesh™ Synthetic Surgical Mesh is about 4 cm×7 cm and knitted from a supple polyester material coated with silicone, the knitted mesh having a pore size that allows for tissue ingrowth during chronic implantation. The InVance™ Male Urethral sling System includes four to six, typically, titanium bone screws and a disposable, battery powered, inserter or driver. Each bone screw has a distal self-tapping spiral thread and a length of No. 1 Prolene suture extending proximally from the bone screw.
In the implantation procedure, the patient is first placed in the lithotomy position and draped, and the surgical field is prepared. A 16 French Foley catheter, for example, is inserted into the urethra, the catheter balloon is inflated t to assist the surgeon in identifying the urethra during dissection, and the scrotum is elevated. A vertical incision is made over the midline in the perineum, and the skin and subcutaneous tissues are dissected free. The bulbocavernous muscle is then exposed, and dissection is carried out posteriorly to the area of the transverse perineum to completely free the bulbar urethra. Lateral dissection is used to expose the corpora cavernosum and the descending pubic rami.
The six titanium bone screws or anchors are then screwed, one at a time, into the inner portion of the descending pubic rami of the pubic bone using the battery-powered driver. The bone screws are screwed fully into the pubic bone so that the No. 1 Prolene sutures extend outward from each bone. The location of each bone screw and the order of bone screw insertion can be selected by the surgeon. In one approach, the first pair of bone screws is inserted just below the symphysis, the second pair is inserted just proximal to the level of the ischial tuberosity, and the third pair is inserted intermediate the first and second pair.
The InteMesh™ Synthetic Surgical Mesh is then applied against the array of bone screws bridging the lower surface of the bulbar urethra between the descending pubic rami to determine where the sutures will be passed through the mesh pores and tied off. The sutures extending from one of the descending pubic rami may be first passed though selected mesh pores and tied off employing several surgeon's suture knots. Tension is then applied to the other side or end of the urethral sling as it is drawn against the other pubic ramus to determine where the bone screw sutures should be passed through the mesh pores and tied off.
The determination of the appropriate tension may be accomplished using a cough test or Retrograde Perfusion Pressure (RPP) test. To perform a RPP test, the Foley catheter balloon is then deflated, and the Foley catheter is withdrawn and connected to a sterile saline perfusion line. A zero pressure state is obtained by lowering the bag to the level of the symphysis. The tip of the catheter is repositioned at the penoscrotal angle, and the urethral resistance to start of flow or leakage is recorded (by distance of the bag above the level of the symphysis). In patients under anesthesia suffering from sphincter incontinence, the urethral resistance is very low. Tension is then applied to the untied side of the urethral sling by advancing the end of the urethral sling along the sutures toward the bone screws so that the urethral sling bears against the bulbar urethra. The mesh urethral sling compresses the bulbar urethra as it is adjusted in tension to increase urethral resistance to withstand a pressure selected between 30 and 60 cm of water. The sutures are then tied to maintain the selected tension.
The Foley catheter is then advanced to the bladder (which should advance without difficulties), and the wound is irrigated with Bethadine solution and closed in layers. Subsequently, the Foley catheter is removed after 2 hours, and the patient can be discharged home on oral antibiotics and pain medication after completing a successful voiding trial.
The above-referenced '214 and '524 patents also disclose procedures for repairing a cystocele using retropubic and lateral pubic bone anchors. The surgery disclosed in the '214 patent is indicated for patients with grade four cystocele and urethral hypermobility. The procedure repairs the central defect, the lateral defect, approximates the cardinal ligaments to the midline, and creates a urethral sling of the urethra.
After preparation and draping, a Foley catheter is inserted in the bladder. Once the catheter is in place, a “goal post” incision is made. The vertical bars of the goal post extend laterally from the distal urethra to the horizontal bar that is made just proximal to the bladder neck. The vertical bars reach the vaginal cuff.
After creation of the goal post incision, the vaginal wall is dissected free to expose the perivesical fascia laterally and the cardinal ligaments posteriorly. A figure eight 2-0 absorbable suture is applied to approximate the cardinal ligament to the midline without tying it. If an enterocele sac is encountered, it should be repaired at this stage.
The retropubic space is then entered over the periurethral fascia at the level of the vertical bars of the incision, and the urethropelvic ligaments are exposed. Two fascial anchors (the upper pair) are inserted into the tissue of the suprapubic area. Each of these anchors comprises a bone screw having a distal self-tapping screw thread of the type described above with a No. 1 Prolene suture attached to the proximal end of the bone screw.
In an alternative embodiment, at this stage of the procedure, the retropubic space is not open and two bone anchors or screws of the type described above are applied to the inner surfaces of the symphisis using a right angle drill.
After application of the first set of anchors, a second pair of bone anchors or screws of the type described above are applied to the inner surface of the descending pubic rami of the symphysis.
Once the four bone screws are in place, the bladder prolapse is reduced using a moist sponge over a right angle retractor. Alternatively, a Dexon mesh is applied and left in place. The lower pair of Prolene sutures is then used to incorporate the perivesical fascia and the cardinal ligaments area. Interrupted 2-0 absorbable sutures are used to approximate the perivesical fascia to the midline over the Dexon mesh.
A variation on this procedure is set forth in commonly assigned, U.S. Patent Application Publication No 2002/0183762 to provide urethral support and coaptation employing the InFast™ Ultra Transvaginal Urethral sling System for implanting a urethral sling selected from among the InteXen™ Porcine Dermal Matrix or the InteDerm™ Allograft Dermal Matrix or the InteLata™ Allograft Fascia Lata (all available from American Medical Systems, Inc.). The selected urethral sling is intended to be cut to size and in a T-shape to fit between the bone screws and to be attached thereto as described above. The InFast™ Ultra Female Urethral sling System includes four, typically, titanium bone screws and a disposable, battery powered, inserter that positively engages the bone screw to drive it into bone. In this system, a length of No. 1 Prolene suture is passed through a metal ring extending proximally from the bone screw, and the ends of the suture are joined to needles adapted to be passed through the urethral sling. A distal end of a drive shaft of the battery-powered inserter engages the bone screws, and the drive shaft is shaped to enable orientation of the screw threads toward the posterior aspect of the pubic bone. Other types of bone anchors that include a penetrating tip, a shaft, and a suture threaded through the shaft and that are adapted to be inserted into bone are disclosed in commonly assigned U.S. Pat. Nos. 6,635,058 and 6,746,455.
The tensioning of the selected urethral sling is accomplished in this procedure as the suture needles are passed through the urethral sling, and the urethral sling is pressed against the bone surface. The suture needles are severed, and the suture ends are tied together. The tied suture knot is slid upward and posteriorly (behind the bone) to ensure juxtaposition of the sling end to the bone surface.
The above-described bone screws are intended to be driven into the bone until completely embedded with the suture extending out of the self-tapped bore in the bone.
Thus, in the above-described procedures, the urethral sling in maintained in place, and sling tension is adjusted and applied through the tied sutures. The procedure of initially tensioning and tying the sutures takes an undue amount of the surgical time, up to 15-25 minutes as observed in some instances employing the InVance™ Male Urethral Sling System for implanting the InteMesh™ Synthetic Surgical Mesh. Moreover, it is sometimes difficult to achieve the tension in the urethral sling that is sufficient to constrict the urethral sphincter to provide urethral resistance to leakage at the selected water bag height, e.g. at 60 cm.
If the resulting sling tension is not adequate, it may be necessary to untie the tied sutures to readjust tension including possibly repositioning the bone screw in the pubic bone or the sutures extending through the urethral sling. Tying, untying and retying the suture knots consumes further time. Thus, it would be desirable to simplify the process of and to reduce the amount of time that it takes to detach, adjust tension, and reattach the urethral mesh to the sutures extending from bone screws.
Moreover, the sutures may have been trimmed at the knot following an earlier tying. Applying tension through and retying the trimmed sutures may be difficult to accomplish. Therefore, it would be desirable to simplify the process of tensioning and retying the sutures in a manner that is not compromised by trimming the suture length.
In addition, redundant knots are often tied to increase reliability of the suture knot, and the size of the knots so formed can irritate adjacent enervated tissue, causing discomfort to the patient. Consequently, it would be desirable to minimize the physical size of suture fixation of the urethral sling to the bone anchors or screws.
Various types of bone anchors that include a penetrating tip, a shaft, and a head and are adapted to be inserted into bone are disclosed in commonly assigned U.S. Pat. Nos. 6,328,744, 6,387,041, 6,544,273, 6,730,110, and 6,843,796. In certain embodiments disclosed in the '041 patent, for example, the head extends at an angle to the shaft axis, and may comprise laterally extending arms or may comprise a circular plate, a sphere or a half-sphere. In use, the tip is advanced through the sling so that the sling bears against the shaft and is maintained there by the head.
The preferred embodiments of the present invention incorporate a number of inventive features that address the above-described problems that may be combined as illustrated by the preferred embodiments or advantageously separately employed.